//
// Created by 123 on 2025/1/7.
//
#include "iostream"
#include "string"
using namespace std;

void test(){
    string str1 = "i";
    str1+="love game";
    cout << "str1=" << str1 << endl;

    str1 += ':';
    cout << "str1=" << str1 << endl;

    string str2 = "LOL DNF";
    str1 += str2;
    cout << "str1=" << str1 << endl;

    string str3 = "I";
    str3.append("love");
    str3.append("gamesabc",4);
    str3.append(str2,4,3);
    cout << "str3=" << str3 << endl;
}


int main114(){
    test();
    return 0;
}